High voltage integrated circuits (HVICs) in which one or more high voltage transistors are disposed with low voltage circuits on a single chip are being widely applied to power control systems such as switching power supplies and motor drivers. A high voltage integrated circuit (HVIC) includes a high voltage unit, a low voltage unit, and a junction termination disposed between the high voltage unit and the low voltage unit. The junction termination is a region that electrically separates the high voltage unit from the low voltage unit. Level shift devices that level down-shift a signal received from the high voltage unit and provide the signal to the low voltage unit are disposed in the junction termination.
Level shift devices include lateral diffusion MOS (LDMOS) transistors. LDMOS transistors are required to maintain a high breakdown voltage and minimize an on-resistance. By using a reduced surface field (RESURF) technique, a high breakdown voltage may be obtained while an LDMOS transistor has a low on-resistance.